Compression help...

[grnchevyz]

Ok, White smoke coming out of the exhaust...immediately thought Headgasket.

Looked at the plugs, 1,2,3 are nice, 4 is very wet...doesn't smell like gas more like antifreeze.

Compression shows this.

4- 220
3- 218
2- 220
1- 215

I found that weird seeing as the manualy says around 175 for the 4g63t engine. I personally did not do any head/block work yet.

So, I guess my questions are:

1- Are those numbers ok seeing as they are within spec of each other but not to the manual?

2- The wet #4 plug, blown what? Ring? Head gasket?

Let me know...thanks!

 

[andymoraitis]

My guess is you have heavy carbon buildup on the piston crowns which is causing your high readings. Nevertheless, I'd test again with a different tester to rule out errors in the gauge itself. Keep in mind that many heads with blown headgaskets will also register perfect compression. If another tester comes up with the same numbers, I'd Seafoam the motor or leave some MCCC in the cylinders overnight to break up the deposits and bring compression closer to stock levels.

As far as the wetness on plug number four, I'd suspect a head gasket if she's blowing white. If the exhaust smells sweet and you've verified that your smoking issue isn't the result of shaftplay in the turbo, I'd look into the HG next. Just to be safe, I'd do another compression test with another tester, run a leakdown test, check the turbo and then move on to the HG.

Most importantly, you need to know what caused the HG to fail in the first place (if that's the culprit) since it would be pointless to repair it and go through the same thing again. It's usually tuning related so I would look there as well (timing and knock values are a good indicator).

Keep us posted on what you find,

Andy

 

[grnchevyz]

Ok, pulled in my buddy's GST Spyder and his compression showed 200 -205 in all cylinders. So I am assuming that the tester is ok but off by a bit.

In any case, I am still very high on the compression side. Is there anyway to find out if the previous owner changed the pistons at all?

There is no shaft play at all in/out and side-side there is the so called normal play within 1-2 mm.

As for seafoam,,,never done it before...just pour in the cylinders through spark plugs and let it sit overnight?

Let me know!

Thanks for the info btw...

 

[diablos991]

Firs you should try out a different compression tester. That will tell you if yours is faulty. If it is, you need to get a new one.

Search up seafoam. There is a HUGE thread about it and how to use it.

 

[andymoraitis]

The tester's actually off by a pretty significant amount. Spend the pennies to get a new one and re-run the numbers before doing anything else. Once you do that and let us know what they are, we can make frurther recommendations as to whether you need to Seafoam the cylinders or proceed straight to a leakdown test.

Even if the previous owner changed the pistons, he would have needed to install a very high compression setup to come up with numbers like the one's you're seeing.

On a positive note, the turbo sounds OK so we can rule that out for now, but I'd like a bit more info on when the smoke occurs. Is it under boost, at idle, accelerating, decelerating?

 

[diablos991]

Any coolant/oil mixing?

 

[brute]

Yea, you could try draining the oil and checking that out. That'd be my suggestion AFTER you get the new compression tester and get new numbers. Pray for no chocolate milk!!

 

[andymoraitis]

Derek, did you have to go there? Now I have a chocolate milk craving.

Thanks!

 

[grnchevyz]

On a positive note, the turbo sounds OK so we can rule that out for now, but I'd like a bit more info on when the smoke occurs. Is it under boost, at idle, accelerating, decelerating?

Car warmed up, accelerating, no smoke.

Car warmed up, idle, little smoke

Car warmed up, standing still pressing gas, SMOKE!!

Under boost, no smoke while driving.

Decelerating, smoke.

I have another tester on the way, hopefully it'll reveal better results.

 

[andymoraitis]

If the coolant isn't mixing with oil (milky oil or black specs in the coolant) then the problem you're describing sounds like valve stem seals. Once you re-run the compression numbers, I'd have a leakdown test performed. At that point you can isolate the real cause. In general though, smoke on deceleration and at idle is usually an issue with valve steam seals or possibly cracked valve guides. Keep in mind that sometimes when oil burns, it can have a whitish tint to it.

Keep us posted and hang in there. You may not like the diagnosis in the end, but at least you'll know what it is.

 

[grnchevyz]

Can I perform a leakdown test myself or should I bring it to a hsop of some sorts?

Edit: A hsop is a very very advanced shop in Canada

 

[grnchevyz]

Almost forgot...I threw a misfire Cylinder 4 code also but then again #4 plug is completely wet which would explain that...just thought I'd throw that in there...

 

[andymoraitis]

Can I perform a leakdown test myself or should I bring it to a hsop of some sorts?

Edit: A hsop is a very very advanced shop in Canada

Well if you have a great hsop (that was really funny by the way) that you know of I'd bring it to them. A mechanic can usually take care of these pretty easily and if you're not familiar or don't have the equipment that's your best bet.

Does this hsop have a name (sorry, couldn't resist)

 

[grnchevyz]

Ok bought a new tester will retest in the morning and post results.

As for the oil, I pulled the dipstick and well, the oil looked like it was just put in..clear as day ... BUT ...

I decided to re-dip and let the oil run down the dipstick towards the handle and wouldn't you know it, brown milky like stuff running down the stick

That's where I'm at right now, new HG on the way, new valve stem seals OTW also.

I'm guessing an improper tune broke it.

Figure I might as well get DSMLink at the same time to be able to log and all that fun stuff...now regarding that, I have a 95 EPROM ECU, do I need to do anything to the ECU before I can use DSMLink or is it pretty much plug and play minus the plug wire swap?

Thanks again for all the info.

 

[grnchevyz]

OK, new numbers are in.

4- 192
3- 190
2- 190
1- 190

Much better

plug #4 is completely covered in Antifreeze. HG still?

 

[jmakado]

Sure sounds like the HG to me. Possible it let go around a water jacket and is letting coolant into the cylinder but not leaking compression out of that small area.

 

[diablos991]

You will have to get your ECU socketed for dsmlink.
It sounds like the HG to me as well. but its a good call to do the valve stem seals while the head is off the car. (which sounds to me like they are going out as well.

How does the coolant look in your overflow bottle?

 

[andymoraitis]

Compression is still high so it certainly has carbon buildup. I'd run some Seafoam through the BOV line and blow it out to see if compression drops a bit into more normal ranges. Following that, I'd listen to the good advice you received above. It sounds like the HG is toasted. Keep in mind that when an HG fails, it may not always affect compression readings. I'd also follow diablos's advice and replace the valve stem seals in the head while it's off the motor.

It's not too serious and with a little bit of work, you should be good to go again.

 

[grnchevyz]

Ordered a whole gasket set

Going to confirm valve stem seals are there as well.

Thanks for the advice guys, I'll let ya know what I find and fix

 

[andymoraitis]

Good deal. You may want to throw in a new set of ARP's for the head studs if funds allow. It's not a requirement, but it's cheap insurance. Since you'll be taking the head off, I'd simply clean the piston tops at that point. You'll also be able to determine just how much carbon was built up and some pics would help us determine if the excessively high compression numbers are what caused the gasket to fail. Under that much compression, just a little bit of knock would be enough to send it over the edge.

Let us know how it all goes while we cross our fingers.

 

[grnchevyz]

You got it...pics will be coming, I'm gonna pull the head tonight hopefully. ARP's are on the way and arriving in the am.

 

[grnchevyz]

Ok, so I'm getting started on changing the HG and noticed coolant in the TB elbow...hmmmm, trubo seal of some sort gone too? (If so I'm not too worried as I'm installing my EVO3 at the same time.

 

[andymoraitis]

Lou,

Typically if the seals in a turbo are bad you'll see oil in the downpipe and intercooler, not coolant in the throttle body. Since you have coolant lines that run to the throttle body, I'd make sure that the TB is in good shape internally (o-rings and such) before assuming something worse. It could be something as simple as a leaking FIAV (fast idle air valve).

Have a look at some of these threads. Maybe one of them will at least point you in the right direction:

http://www.dsmtuners.com/forums/search.php?searchid=2091028

 

[grnchevyz]

Coolant in the lower IC piping and that's above the bend so with gravity in the equation, it couldn't have come from the top and puddled there...I'll keep going, just reporting in!

 

[diablos991]

hmm. Correct me if I'm wrong, but wouldn't the turbo's center section have to be cracked all of the way through to cause coolant to go into the compressor housing?